package com.van.gateway.handler;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 * @author VanKa qq:2395073039
 * @date 2021/8/18 11:37
 */
@Controller
@RequestMapping("")
public class verificationCode {
    /**
     * 获取验证码图片
     * @param response
     * @param request
     */
    @GetMapping("/token")
    public void getVerificationCode(HttpServletResponse response, HttpServletRequest request) {

        try {

            int width = 200;
            int height = 69;

            BufferedImage verifyImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            //生成对应宽高的初始图片
            String randomText = drawRandomText(width, height, verifyImg);
            //单独的一个类方法，出于代码复用考虑，进行了封装。
            //功能是生成验证码字符并加上噪点，干扰线，返回值为验证码字符
            request.getSession().setAttribute("verifyCode", randomText);
            response.setContentType("image/png");//必须设置响应内容类型为图片，否则前台不识别
            OutputStream os = response.getOutputStream(); //获取文件输出流
            ImageIO.write(verifyImg, "png", os);//输出图片流
            os.flush();
            os.close();//关闭流
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    /*对图片进行处理的类和方法*/
    public static String drawRandomText(int width, int height, BufferedImage verifyImg) {
        Graphics2D graphics = (Graphics2D) verifyImg.getGraphics();
        graphics.setColor(Color.WHITE);//设置画笔颜色-验证码背景色
        graphics.fillRect(0, 0, width, height);//填充背景
        graphics.setFont(new Font("微软雅黑", Font.BOLD, 40));
        //数字和字母的组合
        String baseNumLetter = "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

        StringBuffer sBuffer = new StringBuffer();
        int x = 10;  //旋转原点的 x 坐标
        String ch = "";
        Random random = new Random();
        for (int i = 0; i < 4; i++) {
            graphics.setColor(getRandomColor());
            //设置字体旋转角度
            int degree = random.nextInt() % 30;  //角度小于30度
            int dot = random.nextInt(baseNumLetter.length());
            ch = baseNumLetter.charAt(dot) + "";
            sBuffer.append(ch);
            //正向旋转
            graphics.rotate(degree * Math.PI / 180, x, 45);
            graphics.drawString(ch, x, 45);
            //反向旋转
            graphics.rotate(-degree * Math.PI / 180, x, 45);
            x += 48;
        }
        //画干扰线
        for (int i = 0; i < 6; i++) {
            // 设置随机颜色
            graphics.setColor(getRandomColor());
            // 随机画线
            graphics.drawLine(random.nextInt(width), random.nextInt(height),
                    random.nextInt(width), random.nextInt(height));
        }
        //添加噪点
        for (int i = 0; i < 30; i++) {
            int x1 = random.nextInt(width);
            int y1 = random.nextInt(height);
            graphics.setColor(getRandomColor());
            graphics.fillRect(x1, y1, 2, 2);
        }
        return sBuffer.toString();
    }

    /**
     * 随机取色
     */
    private static Color getRandomColor() {
        Random ran = new Random();
        Color color = new Color(ran.nextInt(256),
                ran.nextInt(256), ran.nextInt(256));
        return color;
    }
}
